The N-alkylated fluorine-containing pyrazolecarboxylic acid derivatives, for example 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid, are valuable intermediates in the field of medicine and agricultural chemicals. The EP Patent No. 2,128,139 B1 provides a process for the preparation of N-alkylated fluorine-containing pyrazolecarboxylic acid of Formula I. The process involves reacting N-alkylated fluorine-containing pyrazolecarbonitrile of Formula II with water.
wherein:
R1 represents an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms or an arylalkyl group which may be substituted; R2 represents a hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms or an arylalkyl group which may be substituted or aryl group which may be substituted; and R3 represents an alkyl group having 1 to 6 carbon atoms which is substituted by at least one fluorine atom.